Thin Films Investigations by Means of Spin-Wave Resonance

Abstract

Magnetic resonance technique may successfully be applied to determine some basic parameters such as g-factor, magnetization Ms or anisotropy energy constant Kui n t h i n m a g n e t i c f r l m s . T h e s e p a r a m e t e r s a r e o b t a i n e d f r o m a ferromagnetic resonance experiment when uniform precession of M$st a k e s place. From spin-wave resonance one may extract very valuable information on the exchange constant A or the surface conditions characterized by the surface anisotropy energy (or pinning parameters p). In fact, it is only spin-wave resonance or similar techniques which allow for measurements of A, p or the coupling constant Kc between ferromagnetic sublayers in multilayered structure. The magnetic phase diagram, temperature dependence of the spin-waves stiffness constant, and the anisotropy energy constant may also be listed as 1ess common examples of spin-wave resonance technique application for the investigation of thin films. This paper presents a theoretical approach to typical examples of experimental results and their interpretation from spin-wave resonance measurements.

Ferromagnetic Resonance in Fe/Zr Multilayers

“…Field derivative of FMR absorption was recorded in the temperature range from about 120 K to 300 K using a standard EPR spectrometer operating at 9 GHz. Standard resonance conditions [6] for magnetic field applied perpendicularly or parallel to the film surface were used for evaluation of the effective magnetization 4πMeff = 4πMs -Hu and the g-factor for each resonance of the spectra. The effective magnetization includes the demagnetizing field 4πMs as well as the uniaxial anisotropy term HU that describes the surface and volume anisotropy fields.…”

Magnetic Studies of Polycrystalline Magnetostrictive CoPd Films with Large Planar Strain

“…The field derivative of FMR absorption was recorded. From the resonance positions taken for the static magnetic field applied parallel (H11) and perpendicular (H1) to the film plane, the g-factor and the effective magnetization 2πMeff = 4πMs -Hu (Hu = 2Ku/Ms is the perpendicular anisotropy field) were calculated using the standard resonance conditions for thin films [7].…”

Magnetic properties of Fe/Zr multilayers

“…At elevated temperatures, FMR measurements were performed with inert helium atmosphere. Standard reSOnance conditions [6] for magnetic field applied perpendicularly or parallel to the film surface were used for evaluation of the effective magnetization 4?rI& and the g-factor for each resonance of the spectra. The intensity of each resonance in FMR spectrum (doubly integrated field derivative of the absorption) provides us with valuable information as well since it is proportional to the (4?rM,*volume) product for each constituent present in a film [7].…”